Re: [PATCH v3 10/10] selftests/liveupdate: Add a test for preserving tmpfs files

[Pratyush Yadav]

On Wed, Nov 04 2026, David Matlack wrote:

> On 2026-11-04 02:37 PM, Pasha Tatashin wrote:
>> On 11-04 17:59, Pratyush Yadav wrote:
>> > On Tue, Nov 03 2026, David Matlack wrote:
>> > [...]
>> > 
>> > Umm, no way I am reading all this...
>> > 
>> > LLMs are great at generating tests, and I'm not saying there is no value
>> > in this. It is just that this massive code dump is unreviewable by
>> > humans. It is also unfair to the human reviewer because it took many
>> > orders of magnitude less effort to _write_ them with an LLM.
>> > 
>> > What do you all reckon we should do about this? Trust the LLM to get the
>> > testing right? Do we give up human maintenance of tests entirely? Do we
>> > do fault injection to test the tests themselves?
>> > 
>> > Or do we make the tests smaller and more human reviewable?
>> 
>> We need good test coverage, but I believe we can break this patch down 
>> into smaller changes where tested features are incrementally added.
>
> Agreed that it needs to be easier to review, but I'd like to keep the
> coverage. Here's what I have in mind for v4:
>
>  - Move the preserve-side checks that don't need a kexec into
>    liveupdate.c, like Pasha suggested in his earlier reply: which files
>    can be preserved (permissions, read-only and append-only files), the
>    frozen size while preserved, and unpreserve. Those then run with the
>    regular kselftests instead of only in vmtest.sh.
>
>  - Split the rest of luo_tmpfs into several smaller commits that add the
>    tested features incrementally, e.g. one for the test infrastructure
>    and basic retrieve, one for the open() flags and creation checks, and
>    one for block accounting. That makes the series longer, but each
>    commit is a few hundred lines and can be reviewed on its own.
>
> It will still be long, but I think having the test coverage is worth it.

Agreed.

>
> Does that sound reasonable?

Sounds good. But I think practically speaking, it is not possible to
review the tests as carefully as the main changes. I think I'll rely
more on my LLM for those.

-- 
Regards,
Pratyush Yadav